Large numbers of websites are often hosted on a single server. This provides scalability so that required resources, such as memory and processing power, are increased as needed to meet performance demands based on the activity level on each individual website. Memory consumption can create a bottleneck on the website host server. In particular, websites with low activity, such as websites that are accessed only a few times per day or week, still consume memory even though they are idle.
Organizations that host a large number of websites discover that many of the websites are idle most of the time. For example, if an organization provides commercial web-hosting services, many of its customers are probably small businesses. Many small businesses need to have some web presence, but their websites are mostly designed to be a virtual billboard—they do not contain many or any applications, and they are typically visited only rarely. Some might be idle for hours, and some even days or weeks without a single visitor.
In such a situation, having the website active on the server wastes resources. Even a simple, static website typically uses up at least 6-10 MB of memory. A commercial web-hosting organization may run hundreds or thousands of such websites. These websites consume a large amount of memory for websites that rarely get visited. Most web server administrators configure their servers to automatically terminate such a website after a certain idle time.
However, terminating idle websites presents a user-experience problem because, the server must start the website when it receives a request to view the website. The start procedure for a website takes a certain amount of time during which the user has to wait, staring at a blank screen and/or rotating cursor. The startup can take over 10 seconds or more. Because of the start-up time required to reload the application, the delayed response to the request is likely to be noticeable to the user, who expects the website to be readily available on the server. Web users are accustomed to maximum response times on the order of a few seconds or less. Response times that exceed 10 seconds can result in the user losing focus and leaving the website. The startup time duration is frequently determined by the website application, which is not something that could be fixed by simply modifying the server code.